Jan Koum is the one who sold WhatsApp to Facebook for $19 billion. He is the cofounder of most popular and rapidly growing mobile app.
He was born and raised in small village that is outside of Kiev, Ukrain. His father was a construction manager and his mother was a housewife and he was their only child. He along with his mother and grandmother moved to Mountain View, California, when he was only 16 in 1992. His father didn't move with them, he wanted to join them later but he never made it.
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They got a two bedroom apartment with the help of social support (Government) program. To fulfill needs of money Jan Koum's mother worked as babysitter and he himself cleaned the grocery store as cleaner. At the age of 18 Koum got interest in programming and computer networking. He started to learn computer networking and programming from books that he mostly purchased from used book shop. After studying he had to return them back to the book shop.
He was enrolled at San Jose State University and also worked at Ernst & Young as a security tester. In 1997, he was hired by yahoo; he met Brian Acton while working at Ernst & Young as a security tester in the same year.
After two weeks of job at Yahoo as an infrastructure engineer he was dropped out of San Jose State University. Yahoo's server broke (why he was dropped out) while Koum was in his class at University. Yahoo's co-founder David Filo asked him and other members of small team of server engineers to get there and fix server problem.
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He and Brian Acton worked at Yahoo for next 9 years and in September 2007 both left Yahoo. And took a year to travel around South America and played ultimate Frisbee. Both applied to get jobs at Facebook but failed. He bought an iPhone, in January 2009 and realized that seven months old App Store (at that time) was about to spawn a whole new industry of applications.
He talked about his idea of the application with his friend Alex Fishman, over tea, when he visited him. Koum almost immediately chose the name WhatsApp for the application because it sounded like "What's up." On his birthday he incorporated WhatsApp inc. in California.
Since then company grew too much rapidly, even sometimes applications was switched to paid to stop rapid growth and also for the revenue to deal with servers' costs but still lots of people were using it.
Main things that Koum didn't like were advertisements. According to Wired, Jan Koum says, "There's nothing more personal to you than communicating with friends and family, and interrupting that with advertising is not the right solution." Jan Koum has note on the desk at headquarters which says:
No Ads!
No Games!
No Gimmicks!
WhatsApp have a blog post that explains why they don't sell ads.
These (Jan Koum and Brian Acton) are same guys who were rejected by Facebook when they tried to get jobs there. Now Facebook bought WhatsApp, created by rejected ones. This proves, if you have ability to do something and you put all your efforts in doing that, you'll succeed.
Image source: Jan Koum's Twitter